Can a Combination of Convective and Magmatic Heat Transport in the Mantle Explain Io's Volcanic Pattern?

Abstract

Tidal dissipation makes Jupiter's moon Io the most volcanically active body in the Solar system. Most of the heat generated in the interior is lost through volcanic activity. In this study, we aim to answer the questions: Can convection and melt migration in the mantle explain the spatial characteristics of Io's observed volcanic pattern? And, if so, what constraints does this place on the viscosity and thickness of the convective layer? We examine three different spatial characteristics of Io's volcanic activity: i) The presence of global volcanism; ii) the presence of large-scale variations in Io's volcanic activity; and iii) the number of Io's volcanic systems. Our study relies on the assumptions that melt in the mantle controls Io's global volcanism, that the large-scale variations of Io's volcanic activity are caused by non-uniform tidal heating, and that the spatial density of volcanoes correlates with the spatial density of convective anomalies in the mantle. The results show that the observed small and large-scale characteristics of Io's volcanic pattern can be explained by sub-lithospheric anomalies influenced and caused by convective flow. Solutions that allow for active volcanism and Io's specific large-scale variations in volcanic activity range from a thick mantle of a high viscosity (19 10 Pa s) to a thin asthenosphere of a low viscosity (12 10 Pa s). Provided that Io's volcanoes are induced by convective anomalies in the mantle, we find that more than 80% of Io's internal heat is transported by magmatic processes and that Io's upper mantle needs to be thicker than 50 km.

New Global Map of Io’s Volcanic Thermal Emission and Discovery of Hemispherical Dichotomies

“…The distribution of the remaining ∼47 TW of Io's observed thermal emission-a truly vast amount of energy, equivalent to the Earth's total endogenic heat flow (47 ± 2 TW; Davies & Davies 2010)is unknown. It is likely that this thermal emission component originates from near-surface intrusive activity (Veeder et al 2012;Spencer et al 2020;Steinke et al 2020;Spencer et al 2021) or from shallow, recently buried volcanic deposits. It is also expected that the distribution and magnitude from these sources are a function of local volcanic activity, which, in turn, is a function of internal heating pattern.…”

Io's Long‐Wavelength Topography as a Probe for a Subsurface Magma Ocean

“…The observed variation in surface heat flux δF O may be related to the originally produced heat flux δF P by some blurring function B ( l ) that depends on the spherical harmonic degree l (e.g., Steinke, Hu, et al., 2020; Steinke, van Sliedregt, et al., 2020). This assumes that there exists a convective layer beneath the lithosphere (typically the asesthenosphere) that produces its own heat tidally.…”

Inferring Io’s interior from tidal monitoring

“…Strong retroaction between melt-induced tidal heating and melt production may lead to significant lateral variations in both melt content in the asthenosphere and crustal thickness, which may be amplified by bulk viscoelstic response. Convective transport may also strongly affect melt and heat transport (Tackley et al, 2001;Steinke et al, 2020b), making the surface expression of melt and heat production rather complicated (de Pater et al, 2021). Future modeling efforts are required to take into account lateral variations on tidal dissipation rate, including both shear and bulk dissipation and their consequences on melt and heat transport to the surface.…”